This invention relates to manganese activated zinc silicate phosphors. More particularly, it is concerned with variable color manganese activated zinc silicate phosphors which have been modified by the addition of aluminum and phosphorus, with a method for producing such phosphors, and with cathode ray tube display devices utilizing these phosphors.
Manganese activated zinc silicate (commercially designated as P1) is an efficient green-emitting phosphor finding wide application in devices such as data display cathode ray tubes.
U.S. Pat. No. 4,231,892 to Chang et al. discloses phosphors of the P1 type which have been modified by the addition of Group IIIA and Group VA elements to improve cathodoluminescent efficiency.
Individual phosphors which are capable of exhibiting a shift in the color emitted as a result of a change in the current density of cathodoluminescent excitation are known. For example, V. D. Meyer and F. C. Palilla in J. Electrochem. Soc., 116:531-534 (1969) have shown that the cathodoluminescent emission of sulfide-type P-22R shifts toward shorter wavelengths with excitation by electron beams of increasing current density.